The present invention is directed to an apparatus for altering the characteristics of a fluid. In particular, the present invention is directed to an apparatus defining a first flow path and a second flow path. When the fluid follows the first flow path, it reaches an output of the apparatus without an alteration of its characteristics. When the fluid follows the second flow path, the fluid passes through a chamber containing a beneficial agent such that the beneficial agent becomes dispersed in the flowing fluid, thereby altering the fluid's characteristics. The apparatus is constructed such that flow through the second flow path can be selectively controlled.
The delivery of enteral and parenteral products to a patient from a fluid source is well known. Such fluid products can be provided in hangable containers such as bottles and flexible bags having a bottom outlet that is fluidly connected to a drip chamber. The drip chamber in turn is fluidly connected to a flexible tube which in turn delivers the enteral or parenteral product to a patient. For example, an enteral product can be delivered to a patient by way of a nasogastric tube or a feeding tube inserted through a gastrostomy or a jejunostomy while a parenteral product can be delivered by way of a catheter inserted into a patient's vascular system. The parenteral or enteral product is delivered from the container to the patient through the use of gravity or through the use of an infusion pump. Pumps useful in the administration of enteral and parenteral products are well known and include, but are not limited to, rotary peristaltic pumps, piston pumps, and cassette pumps.
Although such parenteral and enteral fluid delivery systems have been used widely in the medical field for many years, they lack a degree of flexibility. That is, in some cases it is desirable to supplement or otherwise alter the contents of enteral or parenteral products with an additional agent or with additional quantities of an agent already contained in the product. Such supplementation or alteration typically requires the use of a specialized delivery system. For example, a piggy-back delivery system can be used in order to provide a bolus of the additional agent to the enteral or parenteral product during administration thereof. Other known sets capable of simultaneously delivering a plurality of fluids from a plurality of sources can be used. However, such systems include additional tubes and ports that can become entangled during use. Further, such systems are typically higher in cost due to the need for additional lengths of tubing and Y-connectors.
Some fluid delivery systems provide for supplementation of the liquid product in a container by providing a port on the container that can be opened, thereby permitting an additional agent, or additional quantities of an agent contained in the product, to be added directly thereto. However, by allowing such direct access to the product, the sterility of the product may be compromised. In the case of parenteral products, sterility must be maintained during delivery to a patient, thus making direct access unacceptable for parenteral products. The sterility of enteral products historically has posed less of a concern to medical professionals. However, there is a growing recognition of the desirability of providing and delivering enteral nutritional products to patients aseptically. Accordingly, it is desirable to provide a method and apparatus for modifying the characteristics of enteral and parenteral products without exposing the products to contamination.
Without a system or apparatus for easily supplementing the contents of a liquid product prior to delivery thereof from a container to a patient, it becomes necessary to provide products having a wider variety of dosages, volumes, and combinations of agents. For this reason, delivery systems such as those described in U.S. Pat. Nos. 4,511,353; 5,318,558; and 5,324,280 have been developed. In these systems, an agent to be delivered parenterally to a patient is contained in a capsule from which it is ejected over time as a result of osmotic infusion. That is, as the capsule is subjected to the presence of a fluid, the contents of the capsule are released into the fluid. U.S. Pat. No. 5,318,558 discloses the use of such a system in the delivery of agents directly into the body by exposing the capsule directly to bodily fluids.
U.S. Pat. No. 5,069,071 describes a formulation chamber in which various forms of sustained release mechanism can be employed to release agents into a parenteral fluid traversing through the formulation chamber, thereby providing for delivery of the supplemental agent to the patient.
In each of the systems disclosed in the above-referenced patents, it is necessary to place the additional, beneficial agent(s) in the flow path of a tubing set prior to delivering fluid to a patient through the tubing set. Thus, in order to delay the introduction of one or more beneficial agents into the flowing fluid, it was necessary to formulate the beneficial agents such that they had a delayed release into the fluid, thereby increasing the cost of formulating the beneficial agent. It is desirable to provide an apparatus that allows for the introduction of beneficial agents in varying amounts and at various times without the need for formulating the beneficial agents such that their release into the flowing fluid is delayed. It also is desirable to provide an apparatus that allows an operator to initiate the introduction of one or more beneficial agents into the flowing fluid on an as-needed basis without the need for opening the apparatus to an external environment thereof.